Hi Jeff,
It can take up to 24 hours for the Office 365 services to provision after you create a new Office 365 account. If the Office 365 account is a newly registered account during 24 hours, you can try activating the Directory Synchronization after 24 hours to check if the issue will persists.
If you still encounter the error after 72 hours, could you please provide the tenant domain via the private message? We can check it from our side.
To request the tenant domain, I have sent a private message with a subject of < Cannot Enable Dirsync on Tenant Domain > to you.
To access the private message:
-Go to the Your details section on the right side of the community site.
-Click Private messages.
-Click the subject title of the response to read the message
Thanks,
Anna Shi